JP2009173792A - Alignment film, liquid crystal display element having the same, and composition for alignment layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alignment film which has an excellent liquid crystal aligning property, and which is scarcely discolored. <P>SOLUTION: An alignment film which is obtained from a varnish containing a component (I) with a photo-aligning property and a heat curing property and a component (II) forming a film not through heat curing, wherein at least the component (I) is a component unevenly distributed to one surface of the film, and which is composed of a component formed of the component (I), unevenly distributed to the one surface, aligned and cured, and the component (II), is provided, and a liquid crystal display element having the alignment film as a liquid crystal alignment film is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an alignment film obtained by photoaligning a component having photoalignment properties.

  Liquid crystal display elements are used in various liquid crystal display devices such as monitors for notebook computers and desktop computers, video camera viewfinders, and projection displays. Recently, they have also been used in televisions. . Furthermore, it is also used as an optoelectronic-related element such as an optical printer head, an optical Fourier transform element, or a light valve. As a conventional liquid crystal display element, a display element using a nematic liquid crystal is mainly used, and the alignment direction of the liquid crystal in the vicinity of one substrate and the liquid crystal in the vicinity of the other substrate are twisted at an angle of 90 degrees. Liquid crystal display elements of (Twisted Nematic) mode, STN (Super Twisted Nematic) mode in which the orientation direction is twisted at an angle of 180 degrees or more, and so-called TFT (Thin-film-transistor) mode using thin film transistors have been put into practical use ing.

  However, these liquid crystal display elements have a narrow viewing angle at which an image can be properly viewed, and when viewed from an oblique direction, the luminance and contrast may decrease, and luminance inversion may occur in a halftone. In recent years, the problems concerning the viewing angle are as follows: 1) TN-TFT type liquid crystal display element using an optical compensation film, 2) VA (vertical alignment) type liquid crystal display element using a vertical alignment and an optical compensation film, and 3) lateral electric field. IPS (In-Plane Switching) type liquid crystal display element (see, for example, Patent Document 1), 4) Optically compensated bend (Optically self-compensated birefringence: OCB) type liquid crystal display element, etc. ing.

  The development of the technology of the liquid crystal display element is achieved not only by simply improving these driving methods and element structures, but also by improving the components used in the liquid crystal display element. Among the components used in the liquid crystal display element, the liquid crystal alignment film is one of the important elements related to the display quality of the liquid crystal display element, and the role of the liquid crystal alignment film as the quality of the liquid crystal display element increases. Is becoming important year after year.

  A liquid crystal aligning film is adjusted with a liquid crystal aligning agent. The liquid crystal aligning agent mainly used at present is a solution obtained by dissolving polyamic acid or soluble polyimide in an organic solvent. After applying such a solution to a substrate, a polyimide-based alignment film is formed by film formation by means such as heating. Various liquid crystal aligning agents other than polyamic acid are also being studied, but they are almost practical in terms of heat resistance, chemical resistance (liquid crystal resistance), coating properties, liquid crystal alignment properties, electrical properties, optical properties, display properties, etc. It has not been converted.

  An important characteristic required for the liquid crystal alignment film in order to improve the display quality of the liquid crystal display element is a voltage holding ratio. When the voltage holding ratio is low, the voltage applied to the liquid crystal during the frame period is lowered, and as a result, the luminance is lowered, which may hinder normal gradation display. Moreover, even if the initial voltage holding ratio is high, there is a problem when the voltage holding ratio (long-term reliability) after the high temperature acceleration test is lowered.

As an attempt to solve the above problems, a method of improving the performance of the liquid crystal alignment film by polymer blending two types of polyamic acids having different surface energy values when used as a film is disclosed (for example, Patent Document 2). . In such a polymer blend, the polyamic acid of the first and second components has a so-called component gradient structure in which the mixing ratio differs in the film thickness direction of the liquid crystal alignment film.

  However, the liquid crystal alignment film includes a step of rubbing (rubbing) the liquid crystal alignment film with a cloth wound around a roller in order to align the liquid crystal composition in a certain direction. This alignment treatment by rubbing has the following problems in manufacturing a liquid crystal display element. First, the static electricity generated by the rubbing operation, the dust adsorbed on the surface of the alignment film, or the impurities that are eluted from the cloth by rubbing deteriorate the characteristics of the liquid crystal display element such as the voltage holding ratio and reduce the reliability of the display. Sometimes. Further, due to the enlargement of the screen, the substrate may be deformed during rubbing, and an area where the rubbing cloth does not contact the liquid crystal alignment film may occur. On the other hand, in a high-definition display, since the pixels become small, the difference in height between the electrodes becomes large, so that uniform alignment processing by rubbing is difficult and may cause display unevenness.

  In recent years, MVA (Multi-domain Vertical Alignment) mode (for example, refer to Patent Document 3), which is developed in order to improve the problem relating to the viewing angle, combines the vertical alignment and the technology of the protruding structure, is used for alignment of liquid crystal by rubbing. Since direction control is unnecessary, there is little deterioration in display quality due to scratches and a decrease in yield when manufacturing liquid crystal display elements, and it is currently the mainstream for TV applications. The protruding structure is manufactured on a substrate with electrodes through a process such as applying a photosensitive resin, forming a film, exposing the resin, and etching. A liquid crystal alignment film for vertically aligning liquid crystals is formed on the protrusion structure thus manufactured. When no voltage is applied, the liquid crystal is oriented perpendicular to the projection surface, and therefore tilted from the perpendicular to the electrode surface by a minute angle. When a voltage is applied, the liquid crystal is aligned along this slightly tilted direction.

  As described above, the protrusion structure plays an important role in regulating the alignment of the liquid crystal in the MVA mode. However, since several steps are necessary for its production as described above, the alignment control of the liquid crystal is more controlled. Various methods have been sought for simple methods. Among them, a method of controlling the pretilt angle of the liquid crystal alignment film by light (for example, see Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, and Non-Patent Document 4) is one of the promising candidates for realizing this. It is thought that it is one.

  Regarding the photo-alignment method in which the alignment treatment is performed by irradiating light, many alignment mechanisms such as a photolysis method, a photoisomerization method, a photodimerization method, a photocrosslinking method have been proposed (for example, Non-Patent Document 5, Patents). Reference 4). However, the photo-alignment method has so far been poor in alignment control ability, and so far only a few have been put to practical use. Regarding the multi-domain alignment, the photo-alignment film has an advantage that it can be easily performed by overlapping light irradiation while using a mask (see, for example, Patent Document 5 and Patent Document 6). However, when it is used as a display element, there is a drawback that the orientation is easily disturbed by light from a backlight or the like. As a photo-alignment film using photo-alignment, for example, a photo-alignment film obtained from a composition containing anisotropically absorbing molecules and a hydrophobic portion (see, for example, Patent Document 7), a cinnamate polymer and a polyimide-based polymer A photo-alignment film obtained from a composition containing molecules (for example, see Patent Document 8) is known.

  Various studies have been made on the use of an azobenzene derivative as a photo-alignment film by a photoisomerization method (see, for example, Patent Document 9 and Patent Document 10). Photo-alignment films using azobenzene derivatives are known to increase the degree of alignment by isomerization when irradiated with light in the state of polyamic acid and then thermally cured, compared to those irradiated with light after thermosetting. (For example, Non-Patent Document 6) Since an azobenzene derivative is highly colored, it is necessary to devise a method for suppressing the coloration when this is used for a liquid crystal display element.

JP-A-6-160878 JP-A-8-43831 Japanese Patent Laid-Open No. 11-242225 JP 2005-275364 A JP-A-7-72484 Japanese Patent Laid-Open No. 9-21456 International Publication No. 97/037273 Pamphlet Special table 2003-529111 gazette JP-A-10-253963 International Publication No. 96/037807 Pamphlet Liq. Cryst. vol. 28, no. 7, 1065 (2001) Liq. Cryst. vol. 29, no. 4, 567 (2002) Mol. Cryst. Liq. Cryst. vol. 410, 275 (2004) Mol. Cryst. Liq. Cryst. vol. 412, 269 (2004) Liquid Crystal, Vol. 3, No. 4, 262 pages, 1999 Mol. Cryst. Liq. Cryst. vol. 412, 293 (2004)

  An object of the present invention is to provide an alignment film having orientation on the surface and reduced coloring.

  In a thermosetting film material in which two or more of a component having a relatively small surface energy and a component having a relatively large surface energy are blended, a component in which anisotropy is induced by light as a component having a relatively small surface energy (I ) Is used as a component having a relatively large surface energy, and component (II) in which anisotropy is not induced by light is applied, and a component gradient structure (a component having a relatively small surface energy on the film surface) is applied by coating a film material when coated. Is irradiated and light is applied to the coating film of the film material on which the component having a relatively large surface energy is unevenly distributed near the substrate, and then the film surface is cured to cause anisotropy. The present inventors have found that the coloration of the film can be reduced by fixing it while maintaining this. At this time, as a component (II) in which anisotropy is not induced by light, it was found that if a material that does not cause a thermal reaction was used, the developed anisotropy could be maintained, and the present invention was completed.

  The present invention has the following configuration.

[1] Component (I) having photo-alignment property and thermosetting property in which molecules are aligned in one direction by light irradiation, and component for forming a film without depending on heat for thermosetting component (I) ( II) is an alignment film composed of the component (I) and the component (II), wherein the component (I) is photo-aligned and further thermally cured. And
An alignment film in which a component obtained by aligning and curing the component (I) is unevenly distributed on the surface.

[2] The component according to [1], wherein when formed on a substrate, the component (I) oriented and cured is unevenly distributed at the air interface and the component (II) is unevenly distributed at the substrate interface. Alignment film.

[3] The alignment film according to [1] or 2], wherein the component (I) is orientation-cured component is polyimide.

[4] The alignment film according to [3], wherein the component (I) obtained by orientation curing is polyimide having a photosensitive group in the main chain.

[5] The alignment film according to [4], wherein the photosensitive group is one or both of an azo group and a triple bond.

[6] The component in which the component (I) is orientation-cured is one or more types represented by the following general formulas (1-1), (1-2), and (2-1) to (2-4). The alignment film according to [5], which is a polyimide containing diamine as a monomer.

In the formula, R ^{1 to} R ⁵ each represent hydrogen, fluorine, CF _3, or a hydrocarbon group having 1 to 30 carbon atoms.

[7] The component in which the component (I) is orientation-cured is at least one selected from the following structural formulas (3-1) to (3-5) and (4-1) to (4-4) The alignment film according to [6], which is polyimide containing diamine as a monomer.

[8] The component obtained by orientation-curing the component (I) is a polyimide that further contains, as a monomer, a diamine having a side chain represented by the following general formula (5). [4] to [7] The alignment film according to any one of the above.

In the general formula (5), R ⁶ represents a divalent organic group selected from the groups represented by the following general formulas (6) and (7).

In General Formula (6), X ¹ and X ² each represent a single bond, O, COO, OCO, NH, CONH, or alkylene having 1 to 12 carbon atoms, and G ¹ and G ² each represent a single bond or carbon number. 3 to
Represents a divalent group containing 1 to 3 rings selected from 12 aromatic rings and alicyclic rings having 3 to 12 carbon atoms, and R ⁷ represents hydrogen, F, CN, OH, or 1 to 30 carbon atoms. Of alkyl, C 1-30 perfluoroalkyl or C 1-30 alkoxy.
However, when ^{X 1, G 1, X 2} , and all G ² is a single bond, R ⁷ is alkyl of 3 to 30 carbon atoms, perfluoroalkyl or 3 to 30 carbon atoms having 3 to 30 carbon atoms When alkoxy is G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁷ is hydrogen or alkyl, and when G ¹ and G ² are both single bonds, X ¹ , X ² and R ⁷ have a total carbon number of 3 or more.

In the general formula (7), R ⁸ represents hydrogen or alkyl having 1 to 12 carbon atoms, each ring A ¹ independently represents 1,4-phenylene or 1,4-cyclohexylene, and Z ¹ and Z ² each independently represents a single bond, CH ₂ , CH ₂ CH ₂ or O, r is an integer of 0-3, s is each independently an integer of 0-5, t1 is an integer of 0-3, t2 Represents an integer of 0 to 3. In addition, any hydrogen in the 1,4-phenylene or 1,4-cyclohexylene may be replaced with an alkyl having 1 to 4 carbon atoms.

[9] The alignment film according to [8], wherein the diamine having a side chain is a diamine represented by the following general formula (8-1) or (8-2).

In general formulas (8-1) and (8-2), R ⁹ represents alkyl having 1 to 20 carbon atoms, l represents 0 or 2, m and n each represents 0 or 1, and Z ³ represents O. Or represents CH ₂ .

[10] The component obtained by orientation curing of the component (I) is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-butanetetracarboxylic acid. [3] to [9], which is a polyimide containing as a monomer one or more selected from dianhydride and 2,3,5-tricarboxycyclopentylacetic acid dianhydride. Alignment film.

[11] The alignment film according to any one of [1] to [10], wherein the component (II) does not have photo-alignment.

[12] The alignment film according to [11], wherein the component (II) is a soluble polyimide, an N-alkyl-substituted polyamic acid, or a polyester acid.

[13] The component (II) contains one or more kinds selected from 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, and 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a monomer. The alignment film according to [12], which is a polyimide.

[14] A component (I) having photo-orientation and thermosetting properties in which molecules are aligned in one direction by light irradiation, and a component that forms a film without depending on heat for thermosetting component (I) ( II) is an alignment film composed of the component (I) and the component (II), wherein the component (I) is photo-aligned and further thermally cured. ,
The component in which the component (I) is orientation-cured is unevenly distributed on the surface,
The component in which the component (I) is oriented and cured is 4,4′-diaminoazobenzene, 1- {4- [4- (4-n-pentylcyclohexyl) cyclohexyl] phenylmethyl} -3,5-diaminobenzene, Is a polyimide obtained from a reaction product of a diamine containing a tetracarboxylic dianhydride containing one or both of pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride ,
The component (II) is one of diamine containing N, N′-dimethylamino-4,4′-diphenylmethane, pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. Or an N-alkyl substituted polyamic acid that is a reaction product with a tetracarboxylic dianhydride containing both, or 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, 3,4'-diamino Diphenylmethane and a diamine containing one or more selected from the group consisting of 4,4′-diaminodiphenylmethane, pyromellitic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3 , 5-tricarboxycyclopentyl acetic acid dianhydride obtained from a reaction product with tetracarboxylic dianhydride containing one or more selected from the group consisting of An alignment film characterized by being a soluble polyimide.

[15] A pair of opposed substrates, a liquid crystal alignment film formed on one or both of the opposing surfaces of the substrate, a liquid crystal layer formed between the liquid crystal alignment films, In a liquid crystal display element having an electrode for applying a voltage to the liquid crystal composition in the liquid crystal layer,
One or both of the liquid crystal alignment films are the alignment films according to any one of [1] to [14].

[16] A composition for an alignment film comprising a photoalignable polyamic acid having a photosensitive group in the main chain or a derivative thereof and a soluble polyimide, N-alkyl-substituted polyamic acid, or polyester acid.

[17] The alignment film composition as described in [16], wherein the photosensitive group is one or both of an azo group and a triple bond.

[18] The photo-alignable polyamic acid or derivative thereof is one or more diamines represented by the general formulas (1-1), (1-2), and (2-1) to (2-4) [17] The alignment film composition as described in [17], wherein

[19] The photo-alignable polyamic acid or a derivative thereof is represented by the structural formulas (3-1) to (3).
-5) and one or more diamines selected from (4-1) to (4-4) as monomers, the composition for alignment film as described in [18].

[20] Any one of [16] to [19], wherein the photo-alignable polyamic acid or derivative thereof further contains a diamine having a side chain represented by the general formula (5) as a monomer. The composition for an alignment film described in the item.

[21] The alignment film composition according to [20], wherein the diamine having a side chain is a diamine represented by the general formula (8-1) or (8-2).

[22] The photo-alignable polyamic acid or derivative thereof is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-butanetetracarboxylic acid bis. The alignment film according to any one of [16] to [21], comprising one or more kinds selected from an anhydride and 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a monomer Composition.

[23] The component (II) contains one or more kinds selected from 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, and 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a monomer. It is a polyimide, The composition for alignment films as described in any one of [16]-[22] characterized by the above-mentioned.

[24] The photo-alignable polyamic acid or derivative thereof is 4,4′-diaminoazobenzene and 1- {4- [4- (4-n-pentylcyclohexyl) cyclohexyl] phenylmethyl} -3,5-diaminobenzene. And a reaction product of a tetracarboxylic dianhydride containing one or both of pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride,
The component (II) is one of diamine containing N, N′-dimethylamino-4,4′-diphenylmethane, pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. Or an N-alkyl substituted polyamic acid that is a reaction product with a tetracarboxylic dianhydride containing both, or 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, 3,4'-diamino Diphenylmethane and a diamine containing one or more selected from the group consisting of 4,4′-diaminodiphenylmethane, pyromellitic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3 , 5-tricarboxycyclopentyl acetic acid dianhydride obtained from a reaction product with tetracarboxylic dianhydride containing one or more selected from the group consisting of It is a soluble polyimide, The composition for alignment films as described in any one of [16]-[23] characterized by the above-mentioned.

  In the present invention, the alignment film refers to a film in which at least constituent molecules on the surface of the film are aligned in one direction. In addition, the component inclination indicates that the proportion of the component changes in the film thickness direction, and the component inclination structure indicates a structure in which the component is inclined.

  According to the present invention, an alignment film having a molecular alignment by photo-alignment on the surface and reduced coloring can be obtained. For example, when the present invention is applied to a liquid crystal alignment film, it is possible to provide a liquid crystal photo-alignment film in which the liquid crystal alignment is the same as that of the prior art and the film color is greatly improved. By using this liquid crystal alignment film, it is possible to provide an element that can be displayed without producing a structure for controlling the alignment of liquid crystal such as a protruding structure, particularly in the VA mode.

The alignment film of the present invention comprises a component (I) having photo-alignment properties and thermosetting properties in which molecules are aligned in one direction by light irradiation, and a film without depending on heat for thermosetting the component (I). In the film of the composition containing the component (II) to be formed, the component (I) is photo-oriented and further heat-cured, and the component (I) is formed by orientation-curing the component (II). A component in which the component (I) is orientation-hardened is unevenly distributed on the surface. In the alignment film of the present invention, the component in which component (I) is oriented and hardened is unevenly distributed on the surface of the film, and the layer of component (I) and component (II) or the main distribution band is adjacent in the film thickness direction. If it is in a positional relationship, a further component may be included.

  Here, “unevenly distributed” means that the component in which the component (I) is orientation-cured is so aligned that the surface of the alignment film is substantially covered with the unidirectional arrangement of molecules in the component in which the component (I) is orientation-cured. Say that it exists on the surface. The uneven distribution of the component in which component (I) is orientation-cured is due to the fact that the alignment defect is not observed when the liquid crystal display element of the present invention is observed with a polarizing microscope (for example, the magnification is 100 times and the optical condition is crossed Nicol). Can be confirmed.

  The component (I) that has been orientation-hardened includes components (I) and (II) that increase the difference in surface energy required for the respective films of components (I) and (II). By using it, a larger amount can be present on the surface of the alignment film, and a smaller amount can be present on the surface of the alignment film by using the components (I) and (II) that reduce the difference in surface energy. In addition, by using the component (I) having a surface energy smaller than that of the component (II), the component (I) that is orientation-hardened when the alignment film is formed on the substrate surface is unevenly distributed at the air interface of the alignment film. By using the component (I) having a surface energy larger than that of the component (II), the component in which the component (I) is orientation-hardened when the alignment film is formed on the substrate surface is unevenly distributed on the substrate interface. Can do.

The difference between the surface energy of the component (I) film and the surface energy of the component (II) film is sufficiently large from the viewpoint of sufficiently distributing the component (I) orientation-cured component on the alignment film surface. For example, preferably ² mJ / m ² or more, and more preferably 10 mJ / m ² or more. For each component film, the respective coating films of the solutions of components (I) and (II) are formed so that the resulting film thickness is about 60 nm. The surface energy of the film of each component can be prepared by firing under conditions for curing (I), based on the method described in paragraph 0100 of JP-A No. 2004-143051 and pure water and It can be determined from the measured value of the contact angle between ethylene glycol and the film of each component.

  In the alignment film of the present invention, the content of the component obtained by orientation hardening of the component (I) is the component (I) before thermosetting from the viewpoint of imparting sufficient orientation to the film surface and preventing its deterioration over time. In addition, the content of component (I) relative to the total amount of component (II) is preferably 8% by weight or more, and more preferably 10% by weight or more. The content of the component (II) in the alignment film is preferably 50% by weight or more with respect to the component (I) before thermosetting, from the viewpoint of reducing the coloration of the alignment film, and is 70% by weight or more. More preferably.

  The component in which the component (I) is orientation-cured is a component obtained by thermosetting after the molecules are aligned in one direction by irradiating the component (I) before thermosetting with light. The thermosetting means the thermosetting of the component (I), and means that the film of the component (I) is heated so as to cause a curing reaction such as ring closure or crosslinking in the component (I). The component in which the component (I) is orientation-cured may be a component having a photo-orientation property and a thermosetting property in the precursor, that is, the component (I). It may be a mixture of compounds. Moreover, when component (I) is a mixture, it is sufficient that the entire component (I) has photo-alignment properties and thermosetting properties.

Examples of the component in which the component (I) is orientation-cured include, for example, a polyimide containing diamine and tetracarboxylic dianhydride as monomers, and is particularly sensitive to the main chain from the viewpoint of reducing the deterioration of the orientation due to photo-alignment. A polyimide having a group is preferred. The diamine may be one kind or two or more kinds, and the tetracarboxylic dianhydride may be one kind or two or more kinds.

  The photosensitive group is preferably a group arranged in one direction by photoisomerization, and any known photosensitive group can be applied to such a photosensitive group. However, from the viewpoint of high sensitivity to light, the component (I) is preferably an azobenzene derivative, a diphenylacetylene derivative, or a diphenylbutadiyne derivative. Therefore, examples of such a photosensitive group include an azo group and a carbon group. A triple bond is mentioned.

  One of the diamine having a photosensitive group between two amino groups and a tetracarboxylic dianhydride having a photosensitive group between two acid anhydride groups is used as the polyimide having such a photosensitive group in the main chain. Polyimide containing both as monomers can be used. The content of the monomer having a photosensitive group in all the polyimide monomers is preferably 25 mol% or more, and preferably 30 mol% or more from the viewpoint of obtaining sufficient photoalignment. More preferred. The polyimide is, for example, a reaction product of a diamine and a tetracarboxylic dianhydride, and has a photo-alignment property and a thermosetting property having the photosensitive group in one or both of the diamine and the tetracarboxylic dianhydride. An acid or a derivative thereof is obtained by photo-orienting and then thermosetting. In the present specification, “including as a monomer” also means that a constituent unit derived from a monomer is included in the polymer.

  As a diamine having a photosensitive group between two amino groups, for example, diamines represented by the following general formulas (1-1), (1-2), and (2-1) to (2-4) are used as monomers. Including polyimide.

In general formulas (1-1), (1-2), and (2-1) to (2-4), R ^{1 to} R ⁵ are each hydrogen, fluorine, CF _3, or a hydrocarbon having 1 to 30 carbon atoms. Represents a group.

  Examples of the diamines represented by the general formulas (1-1), (1-2), and (2-1) to (2-4) include the following structural formulas (3-1) to (3-5). And diamines represented by (4-1) to (4-4).

  The tetracarboxylic dianhydride having a photosensitive group between the two acid anhydride groups includes, for example, a compound in which two amino groups in the diamine having a photosensitive group between the two amino groups are replaced with acid anhydride groups. Can be mentioned.

  The polyimide diamine having the photosensitive group in the main chain may further contain a diamine other than the diamine having the photosensitive group between the two amino groups. Examples of such other diamines include diamines having side chains and diamines having no side chains. The side chain is a monovalent organic group bonded to a divalent organic group that connects two amino groups.

The diamine having the side chain is a viewpoint of reducing the surface energy of the polyimide containing the diamine as a monomer, a viewpoint of developing a pretilt angle when the alignment film of the present invention is used as a liquid crystal alignment film, and alignment stability. It is preferably used from the viewpoint of expressing various characteristics such as a pretilt angle and electrical characteristics in a balanced manner. For example, from the viewpoint of reducing the surface energy, the content of the diamine having a side chain is preferably 5 to 95 mol%, more preferably 10 to 80 mol%, based on the entire diamine. Further, from the viewpoint of expressing the pretilt angle and particularly vertically aligning the liquid crystal, the content of the side chain diamine is preferably 10 to 70 mol%, preferably 20 to 50 mol% with respect to the whole diamine. Is more preferable. The type of diamine having a side chain can be arbitrarily selected according to not only the purpose as described above but also a target electric characteristic.

Examples of the structure of the side chain in the diamine having the side chain include a group having 3 or more carbon atoms. More specifically,
1) phenyl which may have a substituent, cyclohexylphenylene which may have a substituent, bis (cyclohexyl) phenylene which may have a substituent, alkyl having 3 or more carbon atoms, alkenyl or Alkynyl,
2) phenyloxy which may have a substituent, cyclohexyloxy which may have a substituent, bis (cyclohexyl) oxy which may have a substituent, which may have a substituent Phenylcyclohexyloxy, optionally substituted cyclohexylphenyloxy, or alkyloxy, alkenyloxy or alkynyloxy having 3 or more carbon atoms,
3) phenylcarbonyl, or alkylcarbonyl, alkenylcarbonyl or alkynylcarbonyl having 3 or more carbon atoms,
4) Phenylcarbonyloxy, or alkylcarbonyloxy, alkenylcarbonyloxy or alkynylcarbonyloxy having 3 or more carbon atoms,
5) phenyloxycarbonyl which may have a substituent, cyclohexyloxycarbonyl which may have a substituent, bis (cyclohexyl) oxycarbonyl which may have a substituent, which has a substituent Bis (cyclohexyl) phenyloxycarbonyl which may be substituted, cyclohexylbis (phenyl) oxycarbonyl which may have a substituent, or alkyloxycarbonyl, alkenyloxycarbonyl or alkynyloxycarbonyl having 3 or more carbon atoms,
6) phenylaminocarbonyl, or alkylaminocarbonyl having 3 or more carbon atoms, alkenylaminocarbonyl or alkynylaminocarbonyl,
7) Cyclic alkylene having 3 or more carbon atoms,
8) Cycloalkylalkylene which may have a substituent, phenylalkylene which may have a substituent (provided that phenyl does not have a substituent, alkylene has 2 or more carbon atoms in the linear portion) And when phenyl has a substituent, the alkylene has 1 or more carbon atoms), bis (cyclohexyl) alkylene which may have a substituent, cyclohexylphenylalkylene which may have a substituent , Optionally substituted bis (cyclohexyl) phenylalkylene, optionally substituted phenylalkyloxy, alkylphenyloxycarbonyl, or alkylbiphenylyloxycarbonyl,
9) phenyl or cyclohexyl substituted by alkyl, fluorine-substituted alkyl, or alkoxy, and
10) Alkyl or fluorine in which two or more benzene rings or cyclohexane rings are single-bonded or bonded via —O—, —COO—, —OCO—, —CONH—, or alkylene having 1 to 3 carbon atoms. Examples thereof include, but are not limited to, substituted alkyl or a ring assembly group substituted by alkoxy.

  Here, examples of the “substituent” include alkyl, alkoxy, alkoxyalkyl and the like.

In addition, in these substituents, bis (cyclohexyl) or bis (phenyl) may be interrupted by alkylene.

  In the present specification, the terms “alkyl”, “alkenyl”, and “alkynyl” may be linear or branched.

  Examples of the diamine having a side chain include diamines represented by the following general formula (5).

In the general formula (5), R ⁶ represents a divalent organic group selected from the groups represented by the following general formulas (6) and (7).

In General Formula (6), X ¹ and X ² each represent a single bond, O, COO, OCO, NH, CONH, or alkylene having 1 to 12 carbon atoms, and G ¹ and G ² each represent a single bond or carbon number. Represents a divalent group containing 1 to 3 rings selected from a 3 to 12 aromatic ring and an alicyclic ring having 3 to 12 carbon atoms, R ⁷ is hydrogen, F, CN, OH or carbon number 1 -30 alkyl, a C1-C30 perfluoroalkyl, or a C1-C30 alkoxy is represented. However, when ^{X 1, G 1, X 2} , and all G ² is a single bond, R ⁷ is alkyl of 3 to 30 carbon atoms, perfluoroalkyl or 3 to 30 carbon atoms having 3 to 30 carbon atoms When alkoxy is G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁷ is hydrogen or alkyl, and when G ¹ and G ² are both single bonds, X ¹ , X ² and R ^{7 have} a total carbon number of 3 or more.

In the general formula (6), two amino groups are bonded to the phenyl ring carbon, but the bonding positional relationship between the two amino groups is preferably meta or para. Furthermore, two amino groups are bonded to the 3-position and 5-position, or 2-position and 5-position, respectively, when the bonding position of “R ⁷ -G ² -X ² -G ¹ -X ^1- ” is 1-position. It is preferable.

In the general formula (7), R ⁸ represents hydrogen or alkyl having 1 to 12 carbon atoms, each ring A ¹ independently represents 1,4-phenylene or 1,4-cyclohexylene, and Z ¹ and Z ² each independently represents a single bond, CH ₂ , CH ₂ CH ₂ or O, r is an integer of 0-3, s is each independently an integer of 0-5, t1 is an integer of 0-3, t2 Represents an integer of 0 to 3. 1,4-
Any hydrogen in phenylene or 1,4-cyclohexylene may be replaced by alkyl having 1 to 4 carbon atoms.

  Examples of the diamine having an organic group represented by the general formula (6) and having a side chain include diamines represented by the following general formula (8-1).

In General Formula (8-1), R ⁹ represents alkyl having 1 to 20 carbon atoms, 1 represents 0 or 2, and m and n represent 0 or 1, respectively.

  Examples of the diamine having a side chain having an organic group represented by the general formula (6) include diamines represented by the following general formulas (6-1) to (6-25) and the following structural formula (6-26). ) To (6-31) diamines. In particular, examples of the diamine represented by the general formula (8-1) include diamines represented by the following general formulas (6-1) to (6-11), (6-24), and (6-25). Can be mentioned.

In the general formulas (6-1), (6-2), (6-7), and (6-8), R ²⁰ is preferably alkyl having 1 to ²⁰ carbons or alkoxy having 1 to 20 carbons, An alkyl having 5 to 16 is more preferable. In the general formulas (6-3) to (6-6) and (6-9) to (6-11), R ²¹ is preferably alkyl having 1 to 20 carbons or alkoxy having 1 to 20 carbons, An alkyl of several 3 to 10 is more preferable. In the general formulas (6-12) to (6-14), R ²² is preferably alkyl having 4 to 20 carbons, and more preferably alkyl having 6 to 16 carbons. In general formula (6-15), R ²³ is more preferably alkyl having 6 to 20 carbons or alkyl having 8 to 20 carbons. In the general formula (6-16), R ²⁴ is preferably alkyl having 3 to 20 carbons or alkoxy having 3 to 20 carbons, and more preferably alkyl having 5 to 12 carbons. In the general formulas (6-17) to (6-25), R ²⁵ is preferably alkyl having 1 to 20 carbons or alkoxy having 1 to 20 carbons, and more preferably alkyl having 3 to 10 carbons.

  Of these, diamines represented by general formulas (6-1), (6-2), (6-4), (6-5), and (6-6) are more preferable. Preferably, the diamine represented by general formula (6-1) or (6-2) is mentioned.

  Examples of the diamine having an organic group represented by the general formula (7) and having a side chain include diamines represented by the following general formula (8-2).

In General Formula (8-2), R ⁹ represents alkyl having 1 to 20 carbon atoms, 1 represents 0 or 2, m and n each represents 0 or 1, and Z ³ represents O or CH ₂ . .

  Examples of the diamine having a side chain having an organic group represented by the general formula (7) include diamines represented by the following general formulas (7-1) to (7-16). Particularly as the diamine represented by the general formula (8-2), for example, the following general formulas (7-5), (7-6), (7-8) to (7-10) and (7-12) The diamine represented by these is mentioned.

In the general formulas (7-1) to (7-4), (7-7), (7-11), (7-13) to (7-16), R ²⁶ is a hydrogen atom, having 1 to 1 carbon atoms. 12 alkyls or C1-C12 alkoxy are preferable, and C4-C7 alkyl is more preferable. In the general formulas (7-5), (7-6), (7-8) to (7-10) and (7-12), R ²⁷ is alkyl having 1 to 12 carbons or 1 to 12 carbons. Of alkoxy is preferable, and alkyl having 4 to 7 carbon atoms is more preferable.

  The diamine having no side chain is preferably used from the viewpoint of improving electrical characteristics. For example, from the viewpoint of improving the electrical characteristics, the content of the diamine having no side chain is preferably 50 mol% or less, more preferably 30 mol% or less with respect to the whole diamine. Examples of the diamine having no side chain include diamines represented by the following structural formulas.

  The diamine having no side chain imparts a high VHR to the alignment film of the present invention and suppresses the image sticking phenomenon, so that the structural formulas (V-1) to (V-7) and (VI-1) to It is represented by (VI-12), (VI-26), (VI-27), (VII-1), (VII-2), (VII-6), (VIII-1) to (VIII-5). Diamines represented by the structural formulas (V-6), (V-7), and (VI-1) to (VI-12) are most preferred.

Furthermore, the diamine may further contain a diamine having a polar group shown below. When these diamines are used in the component (I) or (II) of the present invention, their surface energy can be increased. The diamine having a polar group is the other component (II) or (II) having a relatively high polarity relative to one component (I) or (II) having a relatively low polarity among the components (I) and (II). In I), it is preferably used from the viewpoint of further increasing the degree of uneven distribution of the components (I) and (II). The content of the diamine having a polar group is, for example, preferably from 30 to 100 mol%, more preferably from 50 to 100 mol%, based on the whole diamine, from the viewpoint of further increasing the degree of uneven distribution. . Examples of the polar group include substituents containing oxygen and nitrogen, such as COOH, CONH ₂ , OH, CONH, and NH. Examples of the diamine having such a polar group include the following structural formula: Examples thereof include diamines represented by (IX-1) to (IX-22).

  The diamines represented by the structural formulas (IX-1) to (IX-18) are preferable from the viewpoint of relatively easy synthesis. Further, the structural formulas (IX-2), (IX-3), (IX-6), (IX-7), (IX-12), (IX-13), (IX-14), (IX-15) ) And (IX-18) are preferred from the viewpoint of good electrical properties.

  Furthermore, the diamine may further contain a siloxane-based diamine from the viewpoint of improving electrical characteristics when the alignment film of the present invention is used for a liquid crystal alignment film. The siloxane-based diamine is not particularly limited, but is preferably a diamine represented by the following general formula (20) in the present invention.

In the general formula (20), R ³¹ and R ³² each independently represent alkyl or phenyl having 1 to 3 carbon atoms, R ³³ represents methylene, phenylene or alkyl-substituted phenylene, and x is independently 1 Represents an integer of -6, and y represents an integer of 1-10.

  Among these diamines, aromatic (including heteroaromatic ring) diamines in which an amino group is directly bonded to an aromatic ring are particularly preferable because they give good orientation to liquid crystals. Furthermore, the thing of the structure which does not contain oxygen and sulfur, such as an ester and an ether bond which tends to cause the electrical characteristic of a liquid crystal display element to fall is preferable. However, even if it has such a structure, there is no problem as long as the amount is within a range that does not adversely affect the electrical characteristics.

  The tetracarboxylic dianhydride may be one type or two or more types, and aromatic systems (including heteroaromatic ring systems) in which a dicarboxylic acid anhydride is directly bonded to an aromatic ring, and dicarboxylic acid anhydrides are directly bonded to an aromatic ring. It may belong to any group of an aliphatic group (including a heterocyclic group) that is not. The content of the tetracarboxylic dianhydride electrode is preferably 90 to 110 mol%, more preferably 95 to 105 mol%, based on the entire diamine. When the alignment film of the present invention is used as a liquid crystal alignment film, it is preferable that the alignment film of the present invention does not contain oxygen or sulfur such as an ester or an ether bond that easily causes a decrease in electrical characteristics of the liquid crystal display element. Therefore, the tetracarboxylic dianhydride preferably has a structure containing no oxygen or sulfur. However, even if it has such a structure, there is no problem as long as the amount is within a range that does not adversely affect the electrical characteristics.

  Examples of the tetracarboxylic dianhydride include tetracarboxylic dianhydrides represented by the following general formula (9).

  In general formula (9), Q represents a tetravalent group selected from the groups represented by the following general formulas (10) to (18).

In General Formula (10), G ³ represents a single bond, alkylene having 1 to 12 carbon atoms, 1,4-phenylene, or 1,4-cyclohexylene, and X ³ and X ⁴ are each a single bond or CH _2. Represents.

In general formula (11), R ¹⁰ , R ¹¹ , R ¹² and R ¹³ each represent hydrogen, methyl, ethyl or phenyl.

In the general formula (12), ring A ² represents a cyclohexane ring or a benzene ring.

In general formula (13), G ⁴ represents a single bond, CH ₂ , CH ₂ CH ₂ , O, CO, S, C (CH ₃ ) ₂ , or C (CF ₃ ) ₂ , and ring A ³ is independently Represents a cyclohexane ring or a benzene ring.

In the general formula (14), R ¹⁴ represents hydrogen or methyl.

In general formula (15), X ⁵ independently represents a single bond or CH ₂ , and v represents 1 or 2.

In the general formula (16), X ⁶ represents a single bond or CH _2.

In general formula (17), R ¹⁵ represents hydrogen, methyl, ethyl or phenyl, and ring A ⁴ represents a cyclohexane ring or a benzene ring.

  In general formula (18), w1 and w2 each represent 0 or 1.

  Examples of the tetracarboxylic dianhydride that can be preferably used in the present invention include tetracarboxylic dianhydrides represented by the following structural formulas A-1 to A-42.

  The tetracarboxylic dianhydride is a tetracarboxylic dianhydride represented by the structural formula A-1, A-2, or A-7 from the viewpoint of improving the photoalignment in the alignment film of the present invention. The tetracarboxylic dianhydride represented by the structural formula A-1 or A-2 is particularly preferable. In addition, the tetracarboxylic dianhydride has the following structural formulas A-13 and A- from the viewpoint of improving VHR when using the alignment film of the present invention as a liquid crystal alignment film and reducing the coloration of the alignment film. 17, A-18, A-19, A-20, A-27, A-28, A-29, A-31, A-38, A-39, A-40, or A-42 A tetracarboxylic dianhydride is preferable, and a tetracarboxylic dianhydride represented by the following structural formula A-13 or A-17 is particularly preferable.

  The tetracarboxylic dianhydride includes a tetracarboxylic dianhydride having the side chain between two acid anhydride groups and a tetracarboxylic dianhydride having the polar group between two acid anhydride groups. The thing may be further included. These tetracarboxylic dianhydrides can be similarly used for the same purpose as the diamine having a side chain and the diamine having a polar group.

The component (II) is a component that forms a film without relying on heat for thermosetting the component (I). At this time, the component that forms a film without depending on the heat for thermally curing the component (I) is, when a certain component is coated alone, before and after the thermosetting (for example, each structure (for example, This represents a component in which the relative positional relationship of the main chain of the polymer) hardly changes. Specifically, the glass transition point that may have a substituent that reacts at the thermosetting temperature to such an extent that the photo-alignment structure of component (I) is sufficiently maintained during thermosetting of component (I). Are polymers having a temperature equal to or higher than the thermosetting temperature.

  When the alignment film of the present invention is a two-component film of the components (I) and (II), the component (II) is unevenly distributed on the other surface of the film where the component (I) is oriented and cured. In the case where the alignment film of the present invention is a multi-component film having three or more components, the component (II) is adjacent to the component in which the component (I) is oriented and cured in the film thickness direction of the alignment film. It is a component that is unevenly distributed. When the alignment film of the present invention is used as a normal liquid crystal alignment film, it is preferable that the component obtained by aligning and curing the component (I) is unevenly distributed at the air interface and the component (II) is unevenly distributed at the substrate interface.

  The component (II) may have photo-alignment, but it has photo-alignment from the viewpoint of sufficiently reflecting the photo-alignment by the component (I) in the alignment of the alignment film of the present invention. Preferably not. In addition, the component (II) is preferably a component that forms a uniform state such as melting with the component (I) from the viewpoint of sufficiently distributing the component obtained by orientation hardening of the component (I) to the surface of the film. Examples of such component (II) include soluble polyimide, N-alkyl substituted polyamic acid, and polyester acid.

  The soluble polyimide uses, for example, polyamic acid, which is a reaction product of diamine and tetracarboxylic dianhydride, using an equimolar amount of an imidizing agent such as acetic anhydride with respect to the remaining carboxyl group of polyamic acid according to a conventional method. And obtained by imidization. The N-alkyl-substituted polyamic acid can be obtained by reacting a diamine having a monoalkylamino group as two amino groups with tetracarboxylic dianhydride. Furthermore, the polyester acid is obtained by reacting a diol with an acid anhydride. Component (II) can be selected as appropriate based on the surface energy.

  From the viewpoint of preventing the orientation induced by component (I) from being disturbed by the thermal imidization reaction during film formation of component (II), when a soluble polyimide is used for component (II), the imidation rate is It is preferably 50% or more, more preferably 70% or more.

  As the soluble polyimide monomer, the diamine and the tetracarboxylic dianhydride can be used. The monomer of the soluble polyimide can be appropriately selected according to the monomer in the component (I). For example, when a monomer that reduces the surface energy is used in component (I), the soluble polyimide monomer includes a monomer that increases the surface energy (eg, a diamine having no side chain, a diamine having a polar group). , Tetracarboxylic dianhydride having no side chain, and tetracarboxylic dianhydride having a polar group) are preferably used, and when using a monomer that increases the surface energy in component (I), As the monomer for the soluble polyimide, it is preferable to use a monomer for reducing the surface energy (for example, a diamine having a side chain and a tetracarboxylic dianhydride having a side chain).

  The N-alkyl-substituted polyamic acid monomer may be an N-alkyl diamine having a monoalkylamino group as the amino group of the diamine used in the soluble polyimide monomer and the tetracarboxylic dianhydride. it can. The monomer of the N-alkyl-substituted polyamic acid can be appropriately selected according to the monomer in the component (I), similarly to the soluble polyimide.

Among the monomers of the soluble polyimide and the N-alkyl-substituted polyamic acid, the tetracarboxylic dianhydride has the structural formula A- from the viewpoint of improving the solubility of the soluble polyimide or N-alkyl-substituted polyamic acid in the solvent. 13, tetracarboxylic dianhydride represented by A-20, A-28, A-31, A-34, A-35, A-39, A-40, A-41, and A-42 It is preferable. Among these, from the viewpoint of improving VHR of the liquid crystal alignment film, the tetracarboxylic dianhydride preferably includes one or both of the structural formulas A-20 and A-39.

  Examples of such a soluble polyimide include 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, and 2,3,5-trimethyl in the case where the component obtained by orientation-curing component (I) is unevenly distributed at the air interface. A soluble polyimide containing one or more kinds selected from carboxycyclopentylacetic acid dianhydride as a monomer may be mentioned.

  As the polyester acid monomer, the above acid dianhydride and all known diols can be used.

  The alignment film of the present invention irradiates a coating film of a liquid homogeneous mixture containing components (I) and (II) with light from one surface side where component (I) is unevenly distributed in the coating film. It can be obtained by photo-aligning component (I) and thermally curing the photo-aligned component (I). For example, the alignment film of the present invention comprises, as component (I), a photoalignable polyamic acid having a photosensitive group in the main chain or a derivative thereof, and as component (II) soluble polyimide, N-alkyl-substituted polyamic acid, or polyester acid. Can be obtained from an alignment film composition (hereinafter also referred to as “varnish”).

  The photo-alignable polyamic acid or derivative thereof is obtained by reacting the diamine, which is the polyimide monomer of the component (I), with the tetracarboxylic dianhydride. Polyamic acid or derivatives thereof include polyamic acid, partial polyimide in which some amino groups and carboxyl groups of polyamic acid are dehydrated and closed, polyamic acid ester obtained by esterifying part or all of carboxyl groups in polyamic acid, tetra And polyamic acid-polyamide copolymer obtained by reacting a part of carboxylic dianhydride with dicarboxylic acid, and polyamideimide obtained by subjecting a part of the polyamic acid-polyamide copolymer to a dehydration ring-closing reaction. . The polyamic acid or a derivative thereof may be a copolymer such as a random copolymer or a block copolymer.

  For the soluble polyimide, N-alkyl-substituted polyamic acid, and polyester acid in the varnish of the present invention, the respective components described above in the component (II) of the alignment film of the present invention can be similarly used. The soluble polyimide may be a copolymer such as a random copolymer or a block copolymer.

  If the varnish of the present invention forms the alignment film of the present invention described above by light irradiation to the coating film and heating for thermosetting, other components other than the components (I) and (II) are further added. You may contain. Examples of such other components include polyamic acid having no photo-alignment property or a derivative thereof, an organic silicone compound, a crosslinking agent, and a solvent. The polyamic acid having no photo-alignment property can be obtained by reacting the monomer having no photosensitive group, and can be added from the viewpoint of adjusting the physical properties of the alignment film and varnish.

The organic silicone compound is preferable from the viewpoint of adjusting the adhesion of the varnish to the glass substrate. The organosilicone compound added to the varnish of the present invention is not particularly limited. For example, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, N- (2-aminoethyl) -3- Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycyl Silane coupling agents such as Sidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and silicone oils such as dimethylpolysiloxane, polydimethylsiloxane, and polydiphenylsiloxane. It is.

  The content of the organosilicone compound in the varnish is not particularly limited as long as it can improve the adhesion of the alignment film to the substrate without impairing the properties required for the alignment film and varnish of the present invention. Absent. However, if a large amount of these is added, the anisotropy of the film may decrease. Therefore, the content of the organosilicone compound in the varnish is the weight of the polymer contained in the varnish (the total amount of the photoalignable polyamic acid or its derivative and the soluble polyimide, N-alkyl-substituted polyamic acid, or polyester acid). The content is preferably 0.01 to 5% by weight, more preferably 0.1 to 3% by weight.

  The cross-linking agent is preferable from the viewpoint of preventing the deterioration of the properties of the alignment film of the present invention over time and the environment. As the crosslinking agent, a compound that reacts with a carboxylic acid residue of a polyamic acid or a derivative thereof to connect the polyamic acids to each other can be used. Examples of such a crosslinking agent include polyfunctional epoxies and isocyanate materials as described in Japanese Patent No. 3049699, Japanese Patent Application Laid-Open No. 2005-275360, Japanese Patent Application Laid-Open No. 10-212484, and the like. In addition, a material capable of reacting the crosslinking agent itself into a polymer having a network structure and improving the strength of the alignment film in the alignment film of the present invention can be used for the same purpose as described above. Examples of such a crosslinking agent include polyfunctional vinyl ethers, maleimides, and bisallyl nadiimide derivatives as described in JP-A-10-310608 and JP-A-2004-341030. The crosslinking agent used in the present invention may be other than these. Since such a cross-linking agent may impair the orientation of the film at the time of cross-linking, the amount used is the minimum necessary (for example, photo-alignable polyamic acid or a derivative thereof and the soluble polyimide, N-alkyl-substituted polyamic acid, or It is preferable to be 100% by weight or less based on the total amount with the polyester acid.

  The solvent is preferably a solvent that dissolves the photoalignable polyamic acid or a derivative thereof and the soluble polyimide, N-alkyl-substituted polyamic acid, or polyester acid. One type or two or more types of solvents may be used. Examples of such a solvent include N-methyl-2-pyrrolidone (NMP), dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethyl. Examples include formamide (DMF), N, N-diethylformamide, N, N-diethylacetamide (DMAc), and γ-butyrolactone (GBL).

  Examples of other solvents other than the above-mentioned solvents for improving coating properties include alkyl lactate, 3-methyl-3-methoxybutanol, tetralin, isophorone, and ethylene glycol monobutyl ether (BCS). Diethylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ether and diethylene glycol monoethyl ether, ethylene glycol monoalkyl and phenyl acetate, propylene glycol monoalkyl ethers such as triethylene glycol monoalkyl ether and propylene glycol monobutyl ether, and malons such as diethyl malonate Dipropylene glycol monoalkyl ethers such as dialkyl acid and dipropylene glycol monomethyl ether, and these glycol monoethers Ester compounds such as Le acids and the like.

  Among these, NMP, dimethylimidazolidinone, GBL, BCS, diethylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether and the like can be particularly preferably used as the solvent.

  The alignment agent of the present invention may further contain various additives as desired. For example, when a further improvement in coatability is desired, a surfactant suitable for such purpose may be contained, and when a further improvement in antistatic property is required, an appropriate amount of an antistatic agent may be contained.

  Although the density | concentration of the polymer (The photo-alignment polyamic acid or its derivative (s) and the said soluble polyimide, N-alkyl substituted polyamic acid, or polyester acid) in the varnish in this invention is not specifically limited, It is 0.1 to 40 weight%. It is preferable. When the varnish is applied to the substrate, an operation of diluting the contained polymer with a solvent in advance may be required to adjust the film thickness. When the polymer concentration is 40% by weight or less, the viscosity of the varnish is preferable, and when it is necessary to dilute the varnish for adjusting the film thickness, it is preferable because the solvent can be easily mixed with the varnish.

  In the case of a coating method such as a spinner method or a printing method, the polymer concentration is usually 10% by weight or less in order to keep the film thickness good. Other coating methods such as a dipping method or an ink jet method may further reduce the concentration. On the other hand, when the polymer concentration is 0.1% by weight or more, the thickness of the obtained alignment film tends to be preferable. Therefore, the concentration of the polymer is 0.1% by weight or more, preferably 0.5 to 10% by weight in a coating method such as a normal spinner method or printing method. However, depending on the method of applying the varnish, it may be used at a dilute concentration.

  The viscosity of the varnish of the present invention varies depending on the method of application, the concentration of the polymer, the type of polymer used, and the type and proportion of the solvent. For example, in the case of application by a printing press, it is 5 to 100 mPa · s (more preferably 10 to 70 mPa · s). If it exists in this range, sufficient film thickness will be obtained and there will be no printing nonuniformity. In the case of application by ink jet printing, it is 1 to 30 mPa · s (more preferably 5 to 20 mPa · s).

  The molecular weight of the polymer contained in the varnish of the present invention, for example, the weight average molecular weight (Mw) can be arbitrarily selected in order to obtain the desired viscosity of the varnish. However, from the viewpoint of preventing deterioration over time in the alignment film of the present invention, the polyamic acid or derivative thereof including the photo-alignable polyamic acid or derivative thereof contained in the varnish of the present invention, the soluble polyimide, N-alkyl-substituted polyamic acid The Mw of the polyester acid is preferably 10,000 or more. In order to adjust the molecular weight of polyamic acid or its derivative or soluble polyimide, monoamine and / or monocarboxylic acid anhydride may be used in combination with the above monomer. Further, if the molecular weight is too large, the viscosity becomes high and the handling becomes difficult, so the Mw of the polymer is preferably 200,000 or less.

  When Mw needs to be 10,000 or less, it is preferable to introduce a substituent that undergoes a crosslinking reaction during firing into one or both monomers of the polyamic acid or a derivative thereof and a soluble polyimide. For such purposes, a diamine or tetracarboxylic dianhydride having a reactive group described in JP-A-11-193326, a monoamine having a reactive group described in JP-A-1-188528, and It is preferable to use a monocarboxylic acid anhydride together with the raw material. Moreover, you may use the said crosslinking agent for the same objective.

  When it is necessary to make Mw 10,000 or less, introducing a substituent that undergoes polymerization or crosslinking reaction upon irradiation with light into the polyamic acid or soluble polyimide (polyamic acid derivative) makes it possible to align the alignment film of the present invention. More preferred for retention. For such a purpose, the diamine described in International Publication No. 00/06543 or Japanese Patent Application Laid-Open No. 2002-69180 and the monocarboxylic acid anhydride described in Japanese Patent Application Laid-Open No. 11-236451 are combined with the above monomer. It is preferable to use together.

  The alignment film of the present invention includes a step of applying the varnish described above, a step of irradiating the obtained coating film with light to align the photo-alignable polyamic acid or a derivative thereof, and a photo-alignable polyamic acid or a derivative thereof. Can be produced by heating the coated film in which the film is oriented and thermally curing (imidating) the oriented photo-alignable polyamic acid or derivative thereof (component (I)) in the coated film.

  In the present invention, the type of light, the irradiation angle, and the like in the light irradiation step described above are not particularly limited. In the light irradiation step, it is preferable to irradiate light from the surface side of either the air interface or the substrate interface where the photo-alignable polyamic acid or its derivative is unevenly distributed in the coating film. When the alignment film of the present invention is used as a liquid crystal alignment film, it is preferable to irradiate light from an oblique direction with respect to the surface of the alignment film in order to develop a pretilt angle. Further, non-polarized light is particularly preferable as light at this time. According to this step, the photo-alignable polyamic acid or its derivative in the horizontal direction with respect to the surface of the coating film and the polyamic acid in the light incident surface (inclination angle with respect to the substrate surface, perpendicular to the surface of the coating film). It is possible to control both (direction orientation). Further, when it is desired to align the liquid crystal in a direction parallel to the film surface, it is preferable to irradiate linearly polarized light from the direction perpendicular to the surface of the coating film.

  Moreover, you may perform the process which combined the said two methods. This step is preferable from the viewpoint of increasing the degree of orientation of the polyamic acid main chain, which is the material of the alignment film, and obtaining the orientation of the liquid crystal having a uniform pretilt angle.

  In the light irradiation step, the irradiation angle of light irradiated from an oblique direction with respect to the surface of the coating film is not particularly limited, but in order to obtain an arbitrary pretilt angle, the surface of the coating film or The angle of 20 to 70 degrees with respect to the substrate surface is preferable from the viewpoint of obtaining good alignment of the polyamic acid main chain and the pretilt angle of the liquid crystal, and more preferably 30 to 60 degrees.

  As light irradiated in the said light irradiation process, light other than linearly polarized light or linearly polarized light can be used. Examples of light other than linearly polarized light include light in which the intensity ratio of the P-polarized component and S-polarized component is controlled, light in which the P-polarized light and S-polarized light are controlled, and non-polarized light. The light in which the intensity ratio of the P-polarized component and the S-polarized component is controlled includes light having a phase relationship between circularly polarized light and elliptically polarized light, and light having no such phase relationship. It is done. The light other than the linearly polarized light may be any of these lights, and such light is obtained by transmitting through a polarizing filter, a polarizing prism, and a glass plate installed obliquely with respect to the light irradiation direction. Can do.

  Any light source may be used as the light source irradiated in the light irradiation step as long as the object of the present invention is achieved. Examples of such a light source include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, a deep UV lamp, and an excimer laser.

  The wavelength of the light irradiated in the light irradiation step is 300 to 600 nm, more preferably 340 to 500 nm. Photodecomposition of the alignment film is suppressed with light having a wavelength of 300 nm or longer, and photoreaction is likely to proceed with light having a wavelength of 600 nm or shorter. From such a viewpoint, it is preferable to use a short wavelength cut filter, a band pass filter or the like in the light irradiation in the light irradiation step. Moreover, in order to perform a photoreaction efficiently, it is preferable to irradiate ultraviolet light and visible light simultaneously using an ultraviolet / visible continuous light source.

The amount of light irradiated in the light irradiation step depends on the type of coating film, the wavelength of the light source, and the irradiation conditions. As a guideline, the irradiation amount in the case of performing the light irradiation process using a Deep UV lamp and a bandpass filter of 340 to 500 nm is 0.5 J / cm ² or more, preferably 1 J / cm ² or more. Although no particular upper limit irradiation dose, in order to avoid degradation of the orientation film is preferably 2,000 J / cm ² or less, in consideration of the economics of cost and the like related to equipment and processes 300 J / cm ² or less It is preferable that

  As a method for heat-curing the alignment film of the present invention, a generally known method such as a method of performing heat treatment in an oven or an infrared furnace, a method of performing heat treatment on a hot plate, or the like can be applied. In general, the imidization step is preferably performed at a temperature of about 150 to 300 ° C.

  The production of the alignment film of the present invention preferably further includes a step of removing the solvent from the varnish applied to the substrate. The step is preferably performed before the light irradiation step described above, and, as in the imidization step, a method of heat treatment in an oven or an infrared furnace, a method of heat treatment on a hot plate, etc. are generally known. Can be done by any method. In order to prevent the polyamic acid or its derivative from imidizing, this step is preferably performed at a relatively low temperature within a range in which the solvent can be evaporated. In the present invention, this is preferably performed at 100 ° C. or lower for 1 to 10 minutes.

  The manufacture of the alignment film of the present invention may further include a cleaning step using a cleaning liquid after the film is heat-cured. Examples of the cleaning process include jet spray, steam cleaning, and ultrasonic cleaning. These washings may be performed alone or in combination. The cleaning liquid is pure water, alcohols such as methyl alcohol, ethyl alcohol or isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene or xylene, halogenated hydrocarbons such as methylene chloride, or ketones such as acetone or methyl ethyl ketone. Although it can be used, it is not limited to these. Of course, these cleaning solutions are preferably sufficiently purified and have few impurities.

When applied to a liquid crystal alignment film, the alignment film of the present invention is applied to a liquid crystal display element of a system requiring a pretilt angle in the range of 5 to 89.7 degrees, particularly in the range of 80.0 to 89.7 degrees. Is optimal. The pretilt angle can be determined by using, for example, Journal of Applied Physics, Vol. 48 No. 5, p. 1783-1792 (1977), and can be measured by the crystal rotation method. Alternatively, the pretilt angle can be determined according to Mol. Cryst. Liq.
Cryst. 241 (1994) 147. It can be measured by the crystal rotation method described in 1.

  The film thickness of the alignment film in the present invention is usually from 30 to 500 nm from the viewpoints of film thickness uniformity and mechanical, optical, and electrical properties. In order to suppress coloring of the display element due to the film, the thickness of the liquid crystal alignment film is preferably 30 to 200 nm, and more preferably 50 to 150 nm.

  The film thickness of the alignment film of the present invention can be measured by an ordinary film thickness measurement method such as ellipsometry or contact level difference meter. The thickness of the alignment film can be adjusted by adjusting the concentration and viscosity of the varnish and the application conditions of the varnish.

The liquid crystal display element of the present invention is formed between a pair of substrates disposed opposite to each other, the alignment film of the present invention formed on one or both of the opposed surfaces of the substrate, and the alignment film. A liquid crystal layer, and an electrode for applying a voltage to the liquid crystal composition in the liquid crystal layer. The liquid crystal display element in the present invention can be configured in the same manner as a conventional liquid crystal display element except for an alignment film. More specifically, the liquid crystal display element of the present invention is a process of producing an alignment film on a substrate as described above, and then assembling the substrate with a spacer interposed therebetween, and enclosing the liquid crystal composition in a gap between the substrates It is obtained by performing the process of attaching and the process of sticking a polarizing film.

  The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposition films. The electrodes may be formed on the entire surface of the substrate or may be patterned into a desired shape. Examples of the shape of the electrode include a comb shape or a zigzag structure. The electrode may be formed on one of the pair of two substrates, or may be formed on both. The alignment film is formed on the substrate or electrode.

  The liquid crystal layer is formed by enclosing a liquid crystal composition in a gap between a pair of opposing substrates such that the alignment film of the present invention is formed on one or both of the opposing surfaces. In order to uniformly control the thickness of the liquid crystal layer, a spacer which is interposed between the substrates and forms an appropriate interval can be used as necessary. Examples of the spacer include fine particles and sheets made of glass or resin.

  As the liquid crystal composition, various liquid crystal compositions having negative dielectric anisotropy can be used. Preferable examples of such a liquid crystal composition are JP-A-57-114532, JP-A-2-4725, JP-A-4-224858, JP-A-8-40953, and JP-A-8-104869. JP-A-10-168076, JP-A-10-168453, JP-A-10-236989, JP-A-10-236990, JP-A-10-236992, JP-A-10-236993, JP-A-10-236994, JP-A-10-237000, JP-A-10-237004, JP-A-10-237024, JP-A-10-237035, JP-A-10-237075, JP-A-10-237075 10-237076, JP-A-10-237448 (EP967261A1), JP-A-10-237476 JP-A-0-287874, JP-A-10-287875, JP-A-10-291945, JP-A-11-029581, JP-A-11-080049, JP-A-2000-256307, JP-A-2001-2001. No. 019965, JP-A No. 2001-072626, JP-A No. 2001-192657, and the like.

  One or more optically active compounds may be added to the liquid crystal composition for use.

  Moreover, the liquid crystal display element of this invention may have another other member according to the kind of liquid crystal display element. For example, in a liquid crystal element using a thin film transistor (TFT) for color display, a TFT, an insulating film, a protective film, a pixel electrode, and the like are formed on a first transparent substrate, and a pixel is formed on a second transparent substrate. A black matrix, a color filter, a planarization film, a pixel electrode, and the like that block light outside the region are included. In the IPS mode, a black matrix, a color filter, a planarizing film, and the like are provided on a transparent substrate having no electrode. The comb-like electrode installed on the other side is formed by, for example, depositing on a transparent substrate such as glass using a sputtering method of a metal such as Cr and then performing etching using a resist pattern of a predetermined shape as a mask. The

  Furthermore, in the VA mode, there are cases where minute projections are formed on the transparent substrate (so-called MVA mode). However, if the alignment film of the present invention is used, the alignment of the liquid crystal can be performed by the light irradiation treatment combined with masking. Multi-domain can be implemented.

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The diamine and tetracarboxylic dianhydride used in Examples and Comparative Examples are shown in Table 1 below. The following compounds (30), (31), VI-1, VI-2, PMDA (
A-1) and CBTA (A-13) were purified from commercially available compounds and used in experiments. The following compound (32) was synthesized according to JP-A-49-108029, and the following compound (33) was disclosed in JP-A-2002-162630 (Example 2 (“4- (4- (4-propylcyclohexyl) cyclohexyl)). The compound (34), (61), and VIII-2 were synthesized in accordance with J. Org. Chem., Respectively, using “4- (4- (4-pentylcyclohexyl) cyclohexyl) benzene” instead of “benzene”. 50, 4478 (1985), Japanese Patent Laid-Open No. 58-109479 and Japanese Patent Laid-Open No. 11-193346. The polymer was prepared in a nitrogen stream.

Synthesis Example 1 (Preparation of Varnish V1)
Compound 30 (0.4908 g, 2.3135 mmol) and compound 33 (1.505 g, 2.3123 mmol) were placed in a 100 mL four-necked flask and dissolved in 7 g of N-methyl-2-pyrrolidone. While maintaining the temperature of the reaction system at room temperature, PMDA (1.00087 g, 4.6245 mmol) was added and allowed to react overnight. 15 g of γ-butyllactone, 17.5 g of BCS, and 8 g of N-methyl-2-pyrrolidone were added to the obtained varnish and heated to about 80 ° C. Stirring was performed at this temperature until the viscosity reached about 17 mPa · s to prepare a polyamic acid varnish V1 having a polymer component concentration of about 5% by weight. The weight average molecular weight Mw of the polyamic acid in V1 was 31,000.

  The weight average molecular weight (Mw) of the polyamic acid in the varnish was determined using gel permeation chromatography (GPC), 0.6 wt% phosphoric acid-containing DMF as an eluent, a column temperature of 50 ° C., and polystyrene. Measured as a standard solution. The viscosity of the varnish was measured with a rotational viscometer (E type).

Synthesis Examples 2-5 (Preparation of varnish V2-5)
Polyamic acid varnishes V2 to V5 shown in Table 2 below were prepared in the same manner as in Synthesis Example 1.

Synthesis Example 6
Compound 31 (4.389 g, 28.7144 mmol) was placed in a 200 mL four-necked flask and dissolved in 10 g of N-methyl-2-pyrrolidone. While maintaining the temperature of the reaction system at room temperature, CBTA (5.6611 g, 28.7140 mmol) was added and allowed to react overnight. 20 g of N-methyl-2-pyrrolidone and 60 g of γ-butyllactone were added to the obtained varnish. Acetic anhydride (1.4657 g, 14.3569 mmol) was added to this varnish and heated at 100 ° C. for 2 hours to prepare a soluble polyimide varnish V6 having a polymer component concentration of about 10%. The viscosity of V6 was about 9 mPa · s, the weight average molecular weight Mw of the polyimide was 7,000, and the imidization ratio was 81%.

The imidization rate was measured by ¹ H NMR (Bruker BIOSPIN DRX-500). First, the polymer was reprecipitated in pure water, filtered, and washed once with pure water. This sample was vacuum-dried at 100 ° C. for 3 hours. This sample was dissolved in DMSO-d ₆ and NMR was measured at room temperature (total 128 times). The imidation ratio was determined from the ratio of the integral value of ¹ H of the aromatic ring portion of the polymer and the COOH or CONH group.

Synthesis Examples 7 to 10 (Preparation of varnishes V7 to V10)
Soluble polyimide varnishes V7 to V10 shown in Table 3 below were prepared in the same manner as in Synthesis Example 6.

Measurement of surface energy when varnish V1 was used as a film NMP was added to varnish V1 to obtain a solution having a polymer component concentration of about 3% by weight. This was applied to a glass substrate by a spinner method (1,800 rpm, 15 seconds). The coated substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and then further heated in an oven at 230 ° C. for 30 minutes to obtain a film having a thickness of about 60 nm. The contact angle of the obtained film was measured using pure water and ethylene glycol (EG) in accordance with the description of JP-A-2004-143051 (“(4) Measurement of surface energy” in Examples). The surface energy obtained from the obtained contact angle value was 26.2 mJ / m ² .

  Moreover, about varnish V2-10, when the film | membrane was formed similarly to varnish V1 and the surface energy of the obtained film | membrane was calculated | required, it became the value of the following table | surface.

Example 1
5 g of a mixture of varnishes V1 and V3 (weight ratio; V1: V3 = 20: 80) was weighed into a sample bottle and BC was added to make 6.25 g to obtain a mixed varnish. On a transparent glass substrate (2 cm × 3 cm) provided with an ITO electrode on one side, the mixed varnish having a concentration of polyamic acid and soluble polyimide of about 4% by weight was dropped and applied by a spinner method (1,600 rpm, 15 seconds) ). After coating, the substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and then the substrate plane was tilted 45 degrees with respect to the light source and irradiated with non-polarized light (energy of about 5 J / cm ^{2 at} 365 nm). The substrate after light irradiation was heat-treated at 230 ° C. for 30 minutes to obtain an alignment film having a film thickness estimated from the interference color of the film on ITO of about 60 nm.

  Two substrates having the alignment film formed on the ITO electrode are opposed to each other on the surface on which the alignment film is formed, and a gap for injecting the liquid crystal composition is formed between the facing alignment films. In addition, a liquid crystal composition shown below was injected into the gap to assemble a liquid crystal cell C1 (liquid crystal display element) having a cell thickness of 20 μm. The substrates were laminated in the same direction with the left and right sides reversed, where the inclined direction was left and right, and the direction perpendicular to the inclined direction was up and down.

  This liquid crystal cell C1 was subjected to isotropic treatment at 110 ° C. for 30 minutes and cooled to room temperature. When the liquid crystal cell C1 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C1 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed. The pretilt angle of the liquid crystal cell C1 was measured by the above method and found to be 89.4 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. When a voltage (5 V) was applied to the liquid crystal cell C1 and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed in the entire region of the cell, and a clean alignment was obtained. When the liquid crystal cell C1 was rotated in this state, clear light and darkness was observed. This liquid crystal cell C1 had a voltage holding ratio (VHR) of 95.5% and an ion density of 973 pC.

  In this example, the polarization microscope observation was performed under the conditions where the magnification was 100 times and the optical conditions were crossed Nicols.

  The pretilt angle is determined by the above-described J.P. Appl. Phs. , 48, 1783 (1977).

  Further, the VHR was performed by the method described in “Mizushima et al., 14th Liquid Crystal Discussion Meeting Proceedings p78 (1988)”. The measurement was performed by applying a rectangular wave having a gate width of 69 μs, a frequency of 30 Hz, and a wave height of ± 5 V to the cell. The measurement was performed at 60 ° C. This value is an index indicating how much the applied charge is retained after the frame period. If this value is 100%, it indicates that all charges are retained.

  The ion density was measured using a liquid crystal property measuring system 6254 type manufactured by Toyo Technica Co., Ltd. according to the method described in Applied Physics, Vol. 65, No. 10, 1065 (1996). Using a triangular wave with a frequency of 0.01 Hz, measurement was performed at a voltage range of ± 10 V and a temperature of 60 ° C. If the ion density is high, defects such as seizure due to ionic impurities are likely to occur. That is, like the residual charge, the ion density is a physical property value that is an index for predicting the occurrence of image sticking.

Example 2
A liquid crystal cell C2 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V6 (weight ratio; V1: V6 = 20: 80). When this liquid crystal cell C2 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C2 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C2 was measured by the above method and found to be 89.3 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. Further, when a voltage (5 V) was applied to the liquid crystal cell C2 and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed. In addition, clear light and darkness was observed when the liquid crystal cell C2 was rotated in this state.

  The liquid crystal cell C2 had a VHR of 95.5% and an ion density of 901 pC.

Example 3
A liquid crystal cell C3 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V7 (weight ratio; V1: V7 = 20: 80). When this liquid crystal cell C3 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C3 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C3 was measured by the above method and found to be 89.1 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. When a voltage (5 V) was applied to the liquid crystal cell C3 and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed. In addition, clear brightness and darkness were observed when the liquid crystal cell C3 was rotated in this state.

  The liquid crystal cell C2 had a VHR of 95.2% and an ion density of 817 pC.

Example 4
A liquid crystal cell C4 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V8 (weight ratio: V1: V8 = 20: 80). When this liquid crystal cell C4 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C4 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

When the pretilt angle of the liquid crystal cell C4 was measured by the above method, it was 89.2 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. The liquid crystal cell C4 has a voltage (
When 5V) was applied and observed with a polarizing microscope, no schlieren structure due to orientation defects was observed. Further, when the liquid crystal cell C4 was rotated in this state, clear brightness and darkness were observed.

  The liquid crystal cell C4 had a VHR of 95.2% and an ion density of 663 pC.

Example 5
A liquid crystal cell C5 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V2 and V8 (weight ratio; V2: V8 = 20: 80). When this liquid crystal cell C5 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C5 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  When the pretilt angle of the liquid crystal cell C5 was measured by the above method, it was 89.1 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. Further, when a voltage (5 V) was applied to the liquid crystal cell C5 and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed. Further, when the liquid crystal cell C5 was rotated in this state, clear brightness and darkness were observed.

  The liquid crystal cell C5 had a VHR of 97.9% and an ion density of 486 pC.

Example 6
A liquid crystal cell C6 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V9 (weight ratio; V1: V9 = 20: 80). When this liquid crystal cell C6 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C6 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C6 was measured by the above method and found to be 89.3 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. Further, when a voltage (5 V) was applied to the liquid crystal cell C6 and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed. Further, when the liquid crystal cell C6 was rotated in this state, clear brightness and darkness were observed.

  The liquid crystal cell C6 had a VHR of 96.0% and an ion density of 707 pC.

Example 6 '
A liquid crystal cell C6 ′ was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V4 ′ and V8 ′ (weight ratio; V4 ′: V8 ′ = 10: 90). . When this liquid crystal cell C6 ′ was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C6 ′ was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C6 'was measured by the above method and found to be 89.1 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. Further, when a voltage (5 V) was applied to the liquid crystal cell C6 'and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed. Further, when the liquid crystal cell C6 'was rotated in this state, clear contrast was observed.

  This liquid crystal cell C6 'had a VHR of 98.3% and an ion density of 186 pC.

Example 7
The substrate is changed to a glass substrate without an ITO electrode (Corning), and an alignment film having a film thickness of about 60 nm is formed by a mixed varnish of varnish V2 and V8 in the same manner as in Example 5, and the substrate on which this alignment film is formed is formed. UV-Vis spectrum was measured. The UV-Vis spectrum was measured using a UV-Vis spectrum measuring device (JASCO V-660) using a glass substrate on which no alignment film was formed as a reference. The results are shown in FIG.

Comparative Example 1
A liquid crystal cell C7 was produced in the same manner as in Example 1 except that the order of non-polarized light irradiation and heat treatment at 230 ° C. for 30 minutes was reversed in Example 1. When the liquid crystal cell C7 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C7 was measured by the above method and found to be 90.0 degrees. Further, when a voltage (5 V) was applied to the liquid crystal cell C7 and observed with a polarizing microscope, alignment defects were observed at several locations in the entire area of the cell.

  This liquid crystal cell C7 had a VHR of 95.3% and an ion density of 1,050 pC.

Comparative Example 2
A liquid crystal cell C8 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V10 (weight ratio; V1: V10 = 20: 80). When the liquid crystal cell C8 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C8 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C8 was measured by the above method and found to be 89.7 degrees. Further, when a voltage (5 V) was applied to the liquid crystal cell C8 and observed with a polarizing microscope, alignment defects were observed in several places in the entire area of the cell.

  The liquid crystal cell C8 had a VHR of 90.7% and an ion density of 1,540 pC.

Comparative Example 3
A liquid crystal cell C9 was produced in the same manner as in Example 1 except that the mixed varnish of varnishes V1 and V3 was changed to a mixed varnish of V1 and V5 (weight ratio; V1: V5 = 20: 80). When the liquid crystal cell C8 was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell C9 was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed.

  The pretilt angle of the liquid crystal cell C9 was measured by the above method and found to be 89.8 degrees. When a voltage (5 V) was applied to the liquid crystal cell C9 and observed with a polarizing microscope, several alignment defects were observed in several places in the entire area of the cell.

  The liquid crystal cell C9 had a VHR of 91.0% and an ion density of 1,420 pC.

Comparative Example 4
The mixed varnish of varnish V2 and V8 is changed to varnish V4, an alignment film is formed on a glass substrate (Corning) without an ITO electrode in the same manner as in Example 7, and the UV-Vis spectrum of the substrate on which this alignment film is formed Was measured. The results are shown in FIG.

  From the results of Examples 1 to 6 and Comparative Example 1, the varnish containing the component (I) having photo-orientation property and thermosetting property and the component (II) not having both photo-orientation property and thermosetting property. By irradiating non-polarized light from a specific angle and then thermosetting to form an alignment film, a pretilt angle can be expressed in the liquid crystal aligned perpendicular to the glass substrate, and good display is possible It can be seen that a VA mode liquid crystal display element can be obtained.

From the results of Example 4 and Comparative Example 2, the component (I) and the component (II)
By using the component (I) and the component (II) that have a large difference in surface energy value when each component is formed into a film, the component (I) is unevenly distributed on the surface of the film, and further, the surface energy value is a component. By using a relatively small component (I) with respect to (II), the component (I) is unevenly distributed at the air interface and the component (II) is unevenly distributed at the substrate interface, so that the VA mode liquid crystal having good liquid crystal alignment is obtained. It can be seen that a display element is obtained.

  Furthermore, from the results of Examples 1 to 6 and Comparative Example 3, as the component (II) having no photo-alignment property, a material that forms a film without heating by thermosetting of the component (I) can be used. It can be seen that a VA mode liquid crystal display element with good orientation can be obtained.

  Furthermore, from the results of Example 7 and Comparative Example 4, it can be seen that the alignment film of the present invention is less colored than the photo-alignment film composed of a polyamic acid-only layer having a diamine containing azobenzene as a monomer.

It is a figure which shows the UV-Vis spectrum of the board | substrate which has an oriented film in Example 7. FIG. It is a figure which shows the UV-Vis spectrum of the board | substrate which has the alignment film in the comparative example 4.

Claims (24)

A component (I) having a photo-alignment property in which molecules are aligned in one direction by light irradiation and a thermosetting property, and a component (II) that forms a film without depending on heat for thermosetting the component (I); An alignment film comprising the component (I) and the component (II), wherein the component (I) is photo-aligned in a film of the composition containing the composition and further thermally cured,
An alignment film in which a component obtained by aligning and curing the component (I) is unevenly distributed on the surface.   2. The alignment film according to claim 1, wherein when formed on a substrate, the component (I) is oriented and cured, and the component (II) is unevenly distributed at the air interface. 3. .   The alignment film according to claim 1 or 2, wherein the component (I) is an alignment-cured component is polyimide.   4. The alignment film according to claim 3, wherein the component (I) is a polyimide having a photosensitive group in the main chain.   The alignment film according to claim 4, wherein the photosensitive group is one or both of an azo group and a triple bond. The component in which the component (I) is oriented and cured is a monomer of one or more diamines represented by the following general formulas (1-1), (1-2), and (2-1) to (2-4). The alignment film according to claim 5, wherein the alignment film is polyimide.

(Wherein R ^{1 to} R ⁵ each represent hydrogen, fluorine, CF _3, or a hydrocarbon group having 1 to 30 carbon atoms.) The component in which the component (I) is oriented and cured is a monomer of one or more diamines selected from the following structural formulas (3-1) to (3-5) and (4-1) to (4-4) The alignment film according to claim 6, wherein the alignment film is polyimide.

The component in which the component (I) is orientation-cured is a polyimide further containing a diamine having a side chain represented by the following general formula (5) as a monomer. The alignment film described in 1.

(In the general formula (5), R ⁶ represents a divalent organic group selected from the groups represented by the following general formulas (6) and (7).)

(In General Formula (6), X ¹ and X ² each represent a single bond, O, COO, OCO, NH, CONH, or alkylene having 1 to 12 carbon atoms, and G ¹ and G ² represent a single bond or carbon, respectively. Represents a divalent group containing 1 to 3 rings selected from an aromatic ring having 3 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms, R ⁷ is hydrogen, F, CN, OH or carbon number 1-30 alkyl, C1-C30 perfluoroalkyl, or C1-C30 alkoxy is represented.
However, when ^{X 1, G 1, X 2} , and all G ² is a single bond, R ⁷ is alkyl of 3 to 30 carbon atoms, perfluoroalkyl or 3 to 30 carbon atoms having 3 to 30 carbon atoms When alkoxy is G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁷ is hydrogen or alkyl, and when G ¹ and G ² are both single bonds, X ¹ , X ² and R ⁷ have a total carbon number of 3 or more. )

(In the general formula (7), R ⁸ represents hydrogen or alkyl having 1 to 12 carbon atoms, each ring A ¹ independently represents 1,4-phenylene or 1,4-cyclohexylene, and Z ¹ and Z ² each independently represents a single bond, CH ₂ , CH ₂ CH ₂ or O, r is an integer of 0-3, s is each independently an integer of 0-5, t1 is an integer of 0-3, t2 represents an integer of 0 to 3. In addition, any hydrogen in the 1,4-phenylene or 1,4-cyclohexylene may be replaced with an alkyl having 1 to 4 carbon atoms. The alignment film according to claim 8, wherein the diamine having a side chain is a diamine represented by the following general formula (8-1) or (8-2).

(In the general formulas (8-1) and (8-2), R ⁹ represents alkyl having 1 to 20 carbon atoms, 1 represents 0 or 2, m and n each represents 0 or 1, and Z ³ represents Represents O or CH ₂ ) The component in which the component (I) is oriented and cured is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride. And an alignment film according to any one of claims 3 to 9, which is a polyimide containing one or more selected from 2,3,5-tricarboxycyclopentylacetic dianhydride as a monomer.   The alignment film according to claim 1, wherein the component (II) does not have photo-alignment.   The alignment film according to claim 11, wherein the component (II) is a soluble polyimide, an N-alkyl-substituted polyamic acid, or a polyester acid.   The component (II) is a soluble polyimide containing one or more kinds selected from 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, and 2,3,5-tricarboxycyclopentylacetic dianhydride as a monomer. The alignment film according to claim 12. A component (I) having a photo-alignment property in which molecules are aligned in one direction by light irradiation and a thermosetting property, and a component (II) that forms a film without depending on heat for thermosetting the component (I); An alignment film composed of the component (I) and the component (II), wherein the component (I) is photo-aligned and further thermally cured.
The component in which the component (I) is orientation-cured is unevenly distributed on the surface,
The component in which the component (I) is oriented and cured is 4,4′-diaminoazobenzene, 1- {4- [4- (4-n-pentylcyclohexyl) cyclohexyl] phenylmethyl} -3,5-diaminobenzene, Is a polyimide obtained from a reaction product of a diamine containing a tetracarboxylic dianhydride containing one or both of pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride ,
The component (II) is one of diamine containing N, N′-dimethylamino-4,4′-diphenylmethane, pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. Or an N-alkyl substituted polyamic acid that is a reaction product with a tetracarboxylic dianhydride containing both, or 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, 3,4'-diamino Diphenylmethane and a diamine containing one or more selected from the group consisting of 4,4′-diaminodiphenylmethane, pyromellitic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3 , 5-tricarboxycyclopentyl acetic acid dianhydride obtained from a reaction product with tetracarboxylic dianhydride containing one or more selected from the group consisting of An alignment film characterized by being a soluble polyimide. A pair of substrates arranged opposite to each other; a liquid crystal alignment film formed on one or both of the opposing surfaces of the substrate; a liquid crystal layer formed between the liquid crystal alignment films; In a liquid crystal display element having an electrode for applying a voltage to the liquid crystal composition of
One or both of the liquid crystal alignment films are the alignment films according to claim 1.   An alignment film composition comprising a photoalignable polyamic acid having a photosensitive group in the main chain or a derivative thereof and a soluble polyimide, an N-alkyl-substituted polyamic acid, or a polyester acid.   The composition for alignment film according to claim 16, wherein the photosensitive group is one or both of an azo group and a triple bond. The photo-alignable polyamic acid or derivative thereof is one or more kinds of diamines represented by the following general formulas (1-1), (1-2), and (2-1) to (2-4) as monomers. The composition for alignment films according to claim 17, comprising:

(Wherein R ^{1 to} R ⁵ each represent hydrogen, fluorine, CF _3, or a hydrocarbon group having 1 to 30 carbon atoms.) The photo-alignable polyamic acid or derivative thereof is one or more kinds of diamines selected from the following structural formulas (3-1) to (3-5) and (4-1) to (4-4) as monomers. The composition for alignment films according to claim 18, comprising:

The alignment according to any one of claims 16 to 19, wherein the photo-alignable polyamic acid or derivative thereof further contains, as a monomer, a diamine having a side chain represented by the following general formula (5). Film composition.

(In the general formula (5), R ⁶ represents a divalent organic group selected from the groups represented by the following general formulas (6) and (7).)

(In General Formula (6), X ¹ and X ² each represent a single bond, O, COO, OCO, NH, CONH, or alkylene having 1 to 12 carbon atoms, and G ¹ and G ² represent a single bond or carbon, respectively. Represents a divalent group containing 1 to 3 rings selected from an aromatic ring having 3 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms, R ⁷ is hydrogen, F, CN, OH or carbon number 1-30 alkyl, C1-C30 perfluoroalkyl, or C1-C30 alkoxy is represented.
However, when ^{X 1, G 1, X 2} , and all G ² is a single bond, R ⁷ is alkyl of 3 to 30 carbon atoms, perfluoroalkyl or 3 to 30 carbon atoms having 3 to 30 carbon atoms When alkoxy is G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁷ is hydrogen or alkyl, and when G ¹ and G ² are both single bonds, X ¹ , X ² and R ⁷ have a total carbon number of 3 or more. )

(In the general formula (7), R ⁸ represents hydrogen or alkyl having 1 to 12 carbon atoms, each ring A ¹ independently represents 1,4-phenylene or 1,4-cyclohexylene, and Z ¹ and Z ² each independently represents a single bond, CH ₂ , CH ₂ CH ₂ or O, r is an integer of 0-3, s is each independently an integer of 0-5, t1 is an integer of 0-3, t2 represents an integer of 0 to 3. In addition, any hydrogen in the 1,4-phenylene or 1,4-cyclohexylene may be replaced with an alkyl having 1 to 4 carbon atoms. 21. The alignment film composition according to claim 20, wherein the diamine having a side chain is a diamine represented by the following general formula (8-1) or (8-2).

(In the general formulas (8-1) and (8-2), R ⁹ represents alkyl having 1 to 20 carbon atoms, 1 represents 0 or 2, m and n each represents 0 or 1, and Z ³ represents Represents O or CH ₂ )   The photo-alignable polyamic acid or derivative thereof is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, The alignment film composition according to any one of claims 16 to 21, comprising one or more selected from 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a monomer.   The component (II) is a soluble polyimide containing one or more kinds selected from 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, and 2,3,5-tricarboxycyclopentylacetic dianhydride as a monomer. The alignment film composition according to any one of claims 16 to 22, wherein the composition is an alignment film composition. The photo-alignable polyamic acid or a derivative thereof is 4,4′-diaminoazobenzene and 1
A diamine containing-{4- [4- (4-n-pentylcyclohexyl) cyclohexyl] phenylmethyl} -3,5-diaminobenzene, pyromellitic dianhydride and 1,2,3,4-cyclobutanetetra A reaction product with a tetracarboxylic dianhydride containing one or both of a carboxylic dianhydride,
The component (II) is one of diamine containing N, N′-dimethylamino-4,4′-diphenylmethane, pyromellitic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. Or an N-alkyl substituted polyamic acid that is a reaction product with a tetracarboxylic dianhydride containing both, or 3,5-diaminobenzoic acid, 3,5-diaminobenzamide, 3,4'-diamino Diphenylmethane and a diamine containing one or more selected from the group consisting of 4,4′-diaminodiphenylmethane, pyromellitic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3 , 5-tricarboxycyclopentyl acetic acid dianhydride obtained from a reaction product with tetracarboxylic dianhydride containing one or more selected from the group consisting of It is a soluble polyimide, The composition for alignment films as described in any one of Claims 16-23 characterized by the above-mentioned.

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